Dissociative identity disorder is a complex condition associated with severe trauma and disrupted attachment. This case report describes a young woman initially diagnosed with borderline personality disorder and major depressive disorder, later rediagnosed with comorbid dissociative identity disorder. This report details her treatment course with psychodynamic psychotherapy complemented by secondary strategies such as breathing and relaxation exercises. Prognostic implications are discussed, emphasizing how a diagnosis of dissociative identity disorder reshaped her treatment plan. The authors explore the psychodynamics of dissociation and its relational foundations, incorporating perspectives from Chefetz alongside other contributions to the understanding of dissociative identity disorder.